Sarisuluk, two other demonstrators and a police officer are among at least four people killed during the wave of anti-government protests over the past month.
Earlier this month, the European Parliament adopted a resolution criticizing the Turkish government for "the disproportionate and excessive use of force by Turkish police to break up peaceful and legitimate protests."
On Monday, several hundred demonstrators organized a protest march in Istanbul upon receiving news of the release of the suspected shooter of Sarisuluk.
Protesters also organized a Twitter campaign repeating the message, "My name is Ethem Sarisuluk. I was unarmed. Police shot me in the head and I died. They set my murderer free."
The unprecedented violence in Turkey began after riot police repeatedly attacked a group of demonstrators who were protesting against the demolition of a small park in Istanbul. Prime Minister Erdogan had announced plans to replace the park with a shopping mall.
After police launched a predawn raid on the sit-in on May 31 using tear gas and water cannons, demonstrators began fighting back. The violence rapidly escalated and spread to other Turkish cities, as protesters began building barricades, hurling stones, and eventually throwing fireworks and gas bombs at police.
The clashes blossomed into the largest civil disobedience movement Turkey has seen in a generation. Demonstrators have lashed out against what they describe as the increasingly dictatorial policies of Erdogan.
Erdogan first swept to power after his party won national elections more than a decade ago.